Method and Device for the Fracture Separation of a Workpiece

Abstract

A method and a device for fracture separation of a workpiece and a workpiece fracture-separated by the method in accordance with the invention or with the device in accordance with the invention are disclosed. According to the invention, at a distance from a fracture separating notch at least one fracture directing notch is formed, which plays a part in determining the path followed by the fracture separating plane. The device for the fracture separation of the workpiece has a laser unit for forming the fracture separating notch and a mechanical machining unit for forming the fracture directing notch.

1 . A method for fracture separation of a workpiece along a bearing eye, wherein fracture separating notches arranged diametrically to one another are formed in a circumferential wall by way of laser energy, preferably by way of a fiber laser, which fracture separating notches approximately define a fracture separating plane, a crack mandrel being used so as to apply a fracture separating force to the bearing, characterized in that at a distance from the fracture separating notches at least one fracture directing notch is formed that lies in the fracture separating plane, wherein the fracture separating notches are formed circumferentially, and wherein at least one of the fracture separating notch and the fracture directing notch is formed with approximately wavy or zigzag-shaped sections. 
     
     
         2 . The method according to  claim 1 , wherein the fracture directing notch is formed by machining with a cutting tool or electrochemically or by transforming. 
     
     
         3 . The method according to  claim 1 , wherein the workpiece in the area of the fracture separating plane has at least one opening at a circumferential wall of which said fracture directing notch is formed. 
     
     
         4 . The method according to  claim 1 , wherein a laser unit or the workpiece is arranged rotatably relative to the respective other element. 
     
     
         5 . The method according to  claim 1 , wherein the workpiece is partially heated or cooled prior to fracture separation in the area of the fracture separating plane. 
     
     
         6 . The method according to  claim 1 , wherein separation is performed by forming a fatigue crack. 
     
     
         7 . The workpiece produced according to the method  claim 1 , preferably consisting of a fracture-tough material, and/or including a cold-hardened or otherwise pre-treated surface. 
     
     
         8 . The workpiece according to  claim 7 , wherein said workpiece is a connecting rod the large connecting rod eye of which is fracture separated into a bearing shell and a connecting rod-side part, wherein fracture separating notches are formed diametrically to one another on a circumferential wall and wherein a respective fracture directing notch is formed in bolt/screw holes. 
     
     
         9 . The workpiece according to  claim 8 , wherein the fracture separating notch is formed circumferentially. 
     
     
         10 . A device for performing the method according to  claim 1 , including a laser unit for forming a fracture separating notch and a mechanical machining unit for forming a fracture directing notch. 
     
     
         11 . The device according to  claim 10 , wherein the workpiece is located on a turning table, and wherein a laser head is rotatable and/or movable with relation to the workpiece and/or said workpiece is rotatable and/or movable with relation to said laser head. 
     
     
         12 . The device according to  claim 10 , including an oscillating system for applying, during fracture separation, an alternating dynamic force to the expanding mandrel. 
     
     
         13 . The device according to  claim 10 , including a unit for heating or cooling the area of the fracture separating plane. 
     
     
         14 . The workpiece according to  claim 7 , wherein the workpiece is a fracture-tough material including at least one of aluminum alloy and titanium alloy.